Electro-mechanical power unit



Aug' 24, 1965 H. A. sHERwooD ELECTRO-MECHANICAL POWER UNIT Filed Jan. 17, 1961 FIG. 1

FIG. 2

INVENTOR.

HENRY A. SHERWOOD ATTORNEYS United States Patent C) amasar ELECTRdECHANEQAL PWER 'UNET Henry A. Sherwood, Short liiiiis, NJ., assigner to US. Servieator Corporation Piainview, NSI., a corporation of 1Belau/arc Filed dan. 17, 1961, Ser. No. 83,346 5 Claims. (Si. iL-Iidii) rThe present invention relates to power units or prime movers, and particularly to an electro-mechanical prime mover or motor which is cyclically operable and has its intermittent motion translated to effect a predetermined, timed action or series of timed actions.

Power units of the type to which the present invention relates have been suggested heretofore but so far as can be determined they have proved to be impracticable and unreliable because of variables which exist or develop in the inter-relation of heir electrical and mechanical functions. The present invention overcomes this undesirable defect of the prior art by providing a motor constructed to assure its proper and accurate functioning, which is attained by the provision of means for establishing a denite inter-relation of all of its operating parts to effect a xed sequence of action of those parts.

To this end, the present invention in its broad aspects contemplates a power unit having drive and driven means connected by power transmission means, wherein the drive means comprises a bi-metallic element mounted to move in response to the application of heat thereto, and means for applying the heat intermittently to effect a cyclic movement of the bi-metallic element upon its being successively heated and then allowed to cool during each cycle.

More specifically, the invention provides a bi-metallic element surrounded by an electric resistance coil arranged in an electric circuit which is opened and closed by a rockable over-center spring switch, the switch in turn being actuated by the movement of the bi-metallic element to sheet its rocking from on to ofi position, and vice versa. The bi-meta-liic element is equipped with a pawl which engages with the teeth on a ratchet wheel so that when the element moves in response to its being eated by the resistance coil, its movement is translated through the pawl to turn the ratchet wheel. An arm secured to the lai-metallic element and movable with it serves as an anchor for one end of the switch spring, and when the element has moved sufciently to rotate the ratchet wheel through a distance equal to the pitch of the tooth engaged by the pawl, the arm to which the spring is anchored will have moved a distance sufcient to carry the spring beyond center, whereupon it i exerts a force which rocks the switch to break the electric circuit and allow the bimetallic element to cool and return to its original position. in so doing, the spring is returned past center, whereupon it rocks the switch back to its original position to reestablish the electric Contact and open the circuit and commence to next cycle of operation.

It is a prime feature of the invention that the power unit achieves its reliability from the concept of an interrelated adjustability of its operating parts. Thus, the bi-metallic element is adjustable to place itunder ten- Sion or pre-load it beyond the point where it is `affected by the temperature of the atmosphere. Such adjustment determines the initial positions of the element, the driving pawl, the ratchet Wheel and the switch spring anchoring arm; and in this condition of the parts the switch spring is accurately located on the arm, the on and off7 positions of the switch are adjusted to proper locations, vand a holding pawl is adjusted relative to the Patented Aug. 24, 19555 teeth of 'the ratchet wheel, its function being to prevent rotation of tre wheel in a direction reverse to that in which it is being driven.

Other features of the invention need not be enumerated, Since they will be obvious to anyone skilled in the art after reading the following detailed description of the embodiment invention shown in the drawings.

In the accompanying drawings, the invention has been shown merely by Way of example and in preferred form, and obviously many variations and modications may be made therein which will still be comprised within its spirit. it is to be understood, therefore, that the invention is not limited to any speciiic form or embodiment except insofar as such limitations are set forth in the appended claims.

Referring to the drawings,

FG. 1 is a side elevation, showing the working structure of the present invention;

FliG. 2 is a view similar to HG. l, showing the parts in a different position; and

FG. 3 is a modied form of a part of the mechanism shown in FIGS. 1 and 2.

As already stated, the device of the present invention is a very simplified form `of electro-mechanical power unit comprising a drive means 1t?, a driven means 11 and power transmission means i2 connecting the drive means to the driven means. The parts comprising the drive means 1@ are mounted on a support 13 to which they are secured in any suitable manner such as by screws entering from behind the support 13 and therefore not visible in the drawing. A block of insulating material 15 is secured to the upper part of the support 13 and anchored to the block 15, as by screws 1o, is one leg 17 of a bi-metallic element 1S, the other and longer leg 19 of the element 13 depending for a considerable distance below the block 15 in a position to swing relative to the leg 17. Also secured to the block 15, one at each side thereof, are a pair of arms 2@ and 21 which act as stops and may be identified as an on stop 2t) and olf stop 21..

A bracket 222 is secured to the support 13 below and in spaced-apart relation to the block 1S, and at its lower forward edge the bracket 22 is formed with an arm 23 bent outwardly relatively to the support 13 at a right angle to the bracket 22 and drilled and threaded to accommodate an adjusting screw 24, a lock nut 25 being provided to hold the screw 2d in any adjusted position. ri`he free end 26 of the screw 24 extending beyond the arm Z3 is arranged to engage the leg 19 of the bi-metallic element 13 near its free end for the purpose of preloading or placing the leg 19 under a predetermined tension for a purpose to be explained more fully hereinafter. Secured to the leg 19 of the bi-metallic element 1S is an arm 27 arranged to extend rearwardly or toward and alongside but out of contact with the bracket 22. As will be observed, the bottom edge of the arm 27, from its free end and throughout approximately `one-half of its length, is formed with serrations 2&5.

The upper edge of the bracket 22 is formed with a V-shaped notch 2g adapted to serve as a pivot seat for a switch arm 39. As shown in FIG. 1, the switch arm Btl extends from the notch 2d upwardly between the arms 2@ and 21 and its upper end engages the under surface of a fiexible spring contact 31 which is secured to or made as a part of an electric conductor 35 secured to o:the insulated block i5 as by a screw 14. The switch arm 30 is held on the V-shaped seat 29 by a tension spring 32 having one end 33 engaged in an aperture 34 formed in the switch arms and its lower hook-shaped end 34a engaged in one of the serrations 23 on the arm Z7, the spring being under siight tension to exert a downward pull on escasas the switch arm 3i?. The arrangement is what is commonly known as an over-center spring switch.

As alreadyrstated, the contact 31 is secured to the conductor 35 fastened to the block 15, and the conductor 35 is in ContactA with an electric wire 36 also secured by the screw Maud comprising one lead from a source of elec# tric power. A second electric wire 37 leading from the source of electric power is connected to an electrical resistance coil 3S surrounding the leg 19 of the 1oi-metallic element 18, the opposite or lower end of the resistance coil being soldered or otherwise electricallyconnected as at 39to the leg 19 ofthe bi-metallic element 13. Thus, an electric circuit is established whereby electricity is conducted by the lead wire 36 to the conductor 35, through the Contact 31 to the switch arm 30, then through the spring 32 to the arm 27 and the leg 19 of the bi- ;metallic element 18 through the resistance coil 38 and the lead wire 37.

It may be noted that a second conductor 35a is secured to the block 15. In the present instance the second conductor is not hooked into the electric circuit and is, therevfore, ,dea-d'l. If,` for some reason, the on and oit positions of the switch Si) were to be reversed, the lead wire 36 would be connected to the conductor 35a instead of to the conductor 35.

The operation of the power or drive means as thus far described is as follows: With the parts in the position shown in FIG. 1, the leg 19 of the bi-metallic element 18 rests against the free end of the adjusting screw y24, the adjusting screw having been set to move the leg 19 counterclockwise under tension to a predetermined extent equivalent to the amount of movement of the leg 19 which would be effected by the application of a certain amount of heat, say 150 F. This would be a minimum preloading ofthe leg 19 in order to set it beyond the point Where it would be affected by the temperature of the atmosphere. When the leg 19 has been adjusted as just stated, carrying the arm 27 with it, the lower end of the lspring 32 is then located in that serration 28 which lies in the vertical plane of the opening 34 in the switch arm 30,` and lthe spring holds the switch arm under tension against the on stop Ztl land in engagement with the electric contact 31. Thus, in this position of the parts, electric` current will tlow through the circuit already Ydescribed and cause the resistance coil 38 to heat the leg 19 of the bi-metallic element 1S. As the heat thus applied to the leg' 19 rises above 150 F. the leg 19 swings to the right or counterclockwise until it reaches the position shown in FIG. 2. As a result of such movement Vof the leg 19, the arm 27 is also moved in the same direction and carries the lower end of the spring 32 with it untilvit reaches that position (the position shown in FIG. 2) at which point the pull of the spring 32 on-the switch arm 3u causes the'latter to rock with a snap action to the position shown in FIG. 2 where it comes to rest against the oit stop 21. This movement of the switch arm 3) sweeps it out of engagement with the contact 31, breaking the electric circuit, whereupon the application of heat to theleg 19 ceases Yand the latter cools oit. 1n cooling, the leg 19 gradually resumes its initial position, A moving back into contact with the end of the adjusting screw 24. In so moving, it carries the arm 27 and the lower end of the spring 32 with'it and as it comes to rest .againstfthe adjusting screw 24, the spring 32 has been j movedvfar Venough to exert a pull to theleft causing the v switch arm 3Q to rock back against the on stop Ztl and into engagement with the electric contact 31. This reestablishes the electric circuit and the operation of the parts due to the application of heat to the leg 19 as just described is repeated. Such intermittent operation'of the power unit continues for so long a time as electric cur- Y rent is available to ow through the circuit from the wires 36 and 37. The driven vmeans is, in effect, an accumulator, and in the present instance it is shown in its simplest form as comprising a single ratchet wheel et) formed on its periphery with teeth e1, the ratchet wheel 4t) being mounted for rotation on a stud 42 secured to the support 13. Power transmission means in the form of a pawl 1.13 is secured at one end to the leg 19 of the bi-metallic element 18 as by a rivet 14. The pawl 43 is flexible, being madeof material such as spring steel, and has its free end bent to form a nose adapted to engage between the teeth 41 on the ratchet whel 4t?. The spacing of the teeth 41 is such that each movement of the leg 19 during the application of heat thereto will move the ratchet wheel 4t? a distance equal to the pitch of one tooth, and when the leg 19 returns to its initial position` upon cooling, the pawl 43 is carried withit and the nose 45 thereof rides over and `drops in ront of the succeeding tooth on the ratchet wheel 4t).

Aholding pawl t6 is adjustably mounted by a slot and screw connection 47 in fixed position -on the support 13 so that the bent over free end of nose 43 of the pawl 16 engages behind one of the teeth 41 on the ratchet wheel 4?. Each time the ratchet wheel di) is moved a distance of one tooth by the power transmission pawl 43, the nose 410i the pawl to rides over one tooth 41 and drops behind it to prevent reverse rotation of the ratchet wheel t? when the pawl i3 is carried to the left upon the cool- Y ing of the leg 19 of the bi-metallic element 18. Thus,

duringk each heating cycle of the power unit, the ratchet wheel 40 is rotated a distance equal to the pitch of one tooth and heldin that position.

In the embodiment of the invention shown in the drawings, a cam 5t) is carried by or mounted to rotate with the ratchet wheel d@ to actuate a lever 51 pivotally mounted on the support 13 approximately midway of its length, as at 52. One arm 53 of the lever 51 is held in firm engagement with the periphery of the cam by a spring 54. One end 55,01 the spring 5d is hooked into an aperture 56 formed in the arm 57 of the lever 51 and the opposite end thereof is hooked over a pin 58 fixed in the support 13, placing the spring under a slight tension.V ln operation, with the parts in the positions shown in FG. vl, as the ratchet wheel 40 rotates intermittently the cam 511 is rotated therewith and the eccentric portion 59a of its periphery rocks the lever 51 step by step to the dotted line position shown in FIG.l 2. Upon reaching that position, the arm 5'7 of the lever 51 will have been rocked clockwise against the action of the spring 54 to a position where it engages and actuates an electric switch 6i) secured to the support 13 by means of screws 61 (see FIG. 2). When the ratchet wheel et? is next moved by the pawl '43, the eccentric portion 59a of the cam 54E will move out of engagement with end of the arm 53 of the lever 51 and allow the latter to be rocked counterclockwise to the position shown in FIG. l (and by the full lines in FIG. 2) by the relaxation of the spring 54. Continued rotation of the ratchet wheel 40 will be idle according to the embodiment o the invention shown in FIGS. l and 2, with the arm 53 riding Y on the concentric portion 59 of the cam until such time as the eccentric portion 59a reengages the arm 53.

While the single cam 511 shown in FIGS. 1 and 2 may be desirable incertain instances, there may be other instances where it is not desirable to have an idlerrotation of the ratchet wheel 49. Thus, the modification shown in FIG. 3 may be employed wherein the cam is formed with a second eccentric peripheral portion 5%, whereby as the eccentric portion 59a moves away from the arm 530i the lever 51 and allows the latter to be rocked clockwise, the arm 53 drops into engagement immediately with the second eccentric portion 5% of the cam Sii. Thus, with the Vmodiication shown in FlG. 3 one complete rotation of the ratchet wheelttl effects two rocking movements of the lever 51 and two actuations of the switch et).

y The foregoing sets forth the details of an extremely simple and inexpensive power unit or prime mover, the

reliabilityrof which is achieved by the adjustability of its operating parts. Thus, the cycling of the bi-metallic leg 19 is made to occur outside the temperature of the atmosphere, i.e., 150 F. or higher, by adjusting the screw 24 to pre-load the leg 19. Such pre-loading brings the driving pawl 43, ratchet wheel 40 and arm 27, into definite initial positions. With the establishment of the initial position of the ratchet wheel 4t), the holding pawl 46 can be adjusted by means of the slot and screw mounting to locate the nose 48 of the pawl accurately with relation to a tooth 41 on the ratchet wheel, and the lower end of the spring 3421 can be accurately hooked in the proper serration 28 on the arm 27. Furthermore, to assure the proper action of the over-center switch 30, its time of movement away from the on stop 20 must be after the leg 19 through the driving pawl 43 has moved the ratchet wheel 4t) the full distance equal to the pitch of one tooth 41 and the nose 4S of the holding pawl 45 has dropped behind a tooth il on the ratchet wheel. On the other hand, the movement of the switch away from the off stop 21 must be after the leg 19 has cooled and returned completely to rest against the adjusting screw 24 and the driving pawl has dropped in front of the succeeding tooth 41. In the embodiment of the invention shown in the drawings the stops 20 and 21 may be independently adjusted by being bent inward or outward relative to the fixed pivot point, the V-shaped notch 29, of the switch 30 to obtain the proper timing in relation to the extent of movement of the arm 27. If desired, of course each stop 29, 21 could be equipped with an adjusting screw such as the screw 24 to accomplish the same purpose, but that would add to the cost and might involve a problem of accessibility in small, compa-ct units.

It is also pointed out that reliability in the functioning of the power unit 1t? is aided by the utilization of the exible spring form of electric contact 31, which provides for a wiping engagement of the switch arm 30 therewith and thus assures the making of a good contact. In connection with the matter of reliability it has also been found that to insure proper control the driving cycle of the power unit should be taken during the heating phase of the bimetallic leg 19 rather than during the cooling phase.

y As already stated, the invention has been shown in the drawings in its simplest form and as actuating an electric switch 6i) which, in turn, may eiiect the operation of any device to which it is connected. However, instead of rocking a lever the ratchet wheel may operate a multiple gear arrangement whereby the movement of the ratchet wheel 40 is translated to effect the operation of other mechanism after less than one complete rotation of the ratchet wheel 4t? or after many complete rotations thereof, dispensing entirely with the use of a cam or cams to translate the motion of the ratchet wheel. Other mechanisms and their modes of operation will occur to persons skilled in the art and it is not the purpose of this disclosure to set `f-orth in detail `all of the forms of mechanisms with which the power unit may be employed. Itis pointed out, however, lthat the invention provides an electromechanical motor usable to drive means for accomplishing timed kinetic actions, the motor being cycled by a switch controlled by the operation of the motor and whose cyclic operations are accumulated to produce a predetermined result. By way of example, one use could be to connect the wires 36 and 37 to the ignition of an automobile to gave notice (as by the ejection of printed cards from a casing) of the different times when the automobile should be serviced for oil change, ignition inspection, etc. The notice will be according to the length of time that the motor has operated, rather than being based on the speedometer reading or mere lapse of time since the previous servicing.

It should be mentioned that the accurate form of prime mover according to the present invention will find an almost unlimited number of uses in many fields. It has been shown and described herein merely in a simplified form, utilizing a cam action to effect the actuation of an electric switch, which in turn may set into motion any one of a number of conceivable devices for performing a given function. But it has a usefulness whenever and wherever it is desired to perform some function or series of functions under conditions of definite timing. Its use in connection with a privately owned automobile has been mentioned merely by way of example, for its use extends to installations for other purposes in the automotive field such as taxis, rental cars, buses, truck lieets, etc., or in the field of motor boats, aviation, agriculture equipment, etc., in civil government loperations and the armed services; institutions such as hospitals; and many industrial operations. In short, there is a need in all these fields for a reliable, accurate prime mover for effecting timed functions and the present invention supplies that need in an extremely simple and inexpensive mechanism.

Having thus described my invention, what I claim is:

l. A power unit including, in combination, a support, a bi-rnetallic strip mounted with one end iixed to the support and the opposite end free for swinging movement relative -to said fixed end, a rachet wheel mounted on said support for rotation about its axis, a pawl means connected to said element near the free end thereof with an end of said pawl means engaging a tooth on said ratchet wheel, an electric circuit, an electric resistance coil connected in said circuit and arranged to surround a major portion lof said bi-metallic element for applying heat thereto, a switch arranged in said electric circuit and mounted for movement to open and close the circuit, and a connection between the free end of the bi-metallic element and said switch to effect the movement `of the switch in response to the swinging movements of the free end of said element, adjustable means operable to predetermine the minimum degree of heat required to effect initial movement of the bi-metallic element, said support including a bracket, a switch arm pivotally seated on said bracket, an anchor arm connected to and extending from the bi-metallic element toward said bracket in a position below the switch arm, and a vertically disposed spring connected at one end to said switch arm and at its other end to said anchor arm, whereby movement of the bi-metallic arm carries with it the anchor arm and the end of the spring connected thereto and effects an off-center pull on the switch arm to rock it on its pivot.

2. A power unit including, in combination, a support, a bi-meta-llic strip mounted with one end fixed to the support and the opposite end free for swinging movement relative to said fixed end, a ratchet wheel mounted on said support for rotation about its axis, a pawl means connected to said element near the free end thereof with an end of said pawl means engaging a tooth on said ratchet wheel, an electric circuit, an electric resistance coil connected in said circuit and arranged to surround a major portion of said bi-metallic element for applying heat thereto, a switch arranged in said electric circuit and mounted for movement to open and close the circuit, and a connection between the free end of the bi-metallic element and said switch to effect the movement of the switch in response to the swinging movements of the free end of said element adjustable means operable to predetermine the minimum degree of heat required to effect initial movement vof the bi-metallic element, a mechanism adapted for periodic timed operation, and actuating means operated by the movement ofthe ratchet wheel for eecting the timed operation of said mechanism.

3. A combination according to claim 2, wherein the switch arm is rockable from circuit opening to circuit closing positions with heat being applied to said bi-metallic element when said switch arm is in circuit closing position, said pawl means advancing said ratchet wheel during intervals when heat is applied to Vsaid bi-metallic element.

4. A combination according to claim 1, wherein the anchor arm is formed with a plurality of spring holding elements whereby the spring may be selectively connected to any one of them to assure its accurate vertical disposition.

justable stop means for accurately locating the switch `arm in each position.

References Cited by the Eiiaminer UNITED STATES PATENTS 2,435,907 2/48 Schirokauer 310%-4 Olson 310+4 Culberts'en et al '3 itl-it Euler et a1. 310-4 Taylor 310-'4 LLOYD MCCOLL'UM; Primary Examiner.

ORIS L RDEK'Exminer. 

1. A POWER UNIT INCLUDING, IN COMBINATION, A SUPPORT, A BI-METALLIC STRIP MOUNTED WITH ONE END FIXED TO THE SUPPORT AND THE OPPOSITE END FREE FOR SWINGING MOVEMENT RELATIVE TO SAID FIXED END, A RATCHET WHEEL MOUNTED ON SAID SUPPORT FOR ROTATION ABOUT ITS AXIS, A PAWL MEANS CONNECTED TO SAID ELEMENT NEAR THE FREE END THEREOF WITH AN END OF SAID PAWL MEANS ENGAGING A TOOTH ON SAID RATCHET WHEEL, AN ELECTRIC CIRCUIT, AN ELECTRIC RESISTANCE COIL CONNECTED IN SAID CIRCUIT AND ARRANGED TO SURROUND A MAJOR PORTION OF SAID BI-METALLIC ELEMENT FOR APPLYING HEAT THERETO, A SWITCH ARRANGED IN SAID ELECTRIC CIRCUIT AND MOUNTED FOR MOVEMENT TO OPEN AND CLOSE THE CIRCUIT, AND A CONNECTION BETWEEN THE FREE END OF THE BI-METALLIC ELEMENT AND SAID SWITCH TO EFFECT THE MOVEMENT OF THE SWITCH IN RESPONSE TO THE SWINGING MOVEMENTS OF THE FREE END OF SAID ELEMENT, ADJUSTABLE MEANS OPERABLE TO PREDETERMINE THE MINIMUM DEGREE OF HEAT REQUIRED TO EFFECT INITIAL MOVEMENT OF THE BI-METALLIC ELEMENT, SAID SUPPORT INCLUDING A BRACKET, A SWITCH ARM PIVOTALLY SEATED ON SAID BRACKET, AN ANCHOR ARM CONNECTED TO AND EXTENDING FROM THE BI-METALLIC ELEMENT TOWARD SAID BRACKET IN A POSITION BELOW THE SWITCH ARM, AND A VERTICALLY DISPOSED SPRING CONNECTED AT ONE END TO SAID SWITCH ARM AND AT ITS OTHER END TO SAID ANCHOR ARM, WHEREBY MOVEMENT OF THE BI-METALLIC ARM CARRIES WITH IT THE ANCHOR ARM AND THE END OF THE SPRING CONNECTED THERETO AND EFFECTS AN OFF-CENTER PULL ON THE SWITCH ARM TO ROCK IT ON ITS PIVOT. 